function rslt = getLiquidSecurityInSector(opt,varargin)
if opt==1
    %get security with sector
    sector_id=varargin{1};
    all_sec_id = get_info_from_database('security-sector', sector_id);
elseif opt==0
    all_sec_id=varargin{1}
end
    idx_ok = [];            % 
    med_turnover_pct = [];  % 
    % filter the data w/o null
    for i = 1:size(all_sec_id,1)
        rslt = get_info_from_database('daily_stats', 'sec_id', all_sec_id(i));
        if ~isempty(rslt)
            idx_ok = horzcat(idx_ok, i);
            med_turnover_pct = horzcat(med_turnover_pct, rslt.med_turnover_pct);
        end
    end
    % criteria: medium turnover percentage high
    [vals idx] = sort(med_turnover_pct,'descend');
    all_sec_id_ok = all_sec_id(idx);
    rslt = all_sec_id_ok;
end